Chord Randomizer vs 1981 FM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Chord Randomizer
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Chord Randomizer is a powerful music theory practice tool from Nathaniel School of Music. Whether you're a beginner just learning your triads or an advanced musician drilling diatonic progressions, Chord Randomizer keeps your practice sessions fresh and effective. FEATURES - Randomised chord progressions so you never practice the same sequence twice - Three skill levels: Beginner, Intermediate, and Diatonic - Live audio playback with realistic instrument sounds: piano, guitar, harp, and cello - Arpeggio and block-chord playback modes, each with independent volume - Built-in metronome with configurable BPM from 40 to 240 - Playback speed multiplier: 1x, 1.5x, and 2x - Chord rate control: change chords every beat, every bar, or every two bars - Loop mode for continuous practice - MIDI export for use in any DAW - PNG export to share a clean chord chart with students or bandmates - Dark, professional UI optimised for practice sessions PERFECT FOR - Music students building chord recognition - Teachers generating practice exercises - Songwriters and composers exploring new progressions - Guitarists, pianists, and keyboardists of all levels Chord Randomizer runs entirely on-device. No account is needed, and no data is collected.
1981 FM
This app generates complete, unique musical tracks using chaotic mathematical principles. It offers various styles, modes, and keys, with customizable FM synth sounds and effects. Tracks can be recreated using seeds and exported via MIDI.
- Chaos-driven track generation
- Four-operator FM synth engine
- Multiple musical styles and modes
- MIDI export and input
- Customizable effects (chorus, delay, reverb)
- Offline functionality
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1981 FM writes complete tracks. Press generate and you get 64 bars with an intro, verses, choruses, a break and an outro, played by a four-operator FM synth. Lead, bass, arp, pad and a drum machine, through chorus, delay and reverb. Nothing is sampled. Every note is made on the fly and no two tracks come out the same. The music comes from chaos maths. A Lorenz attractor shapes the melody, rhythm and mood. A Hénon map keeps the arpeggio moving. A logistic map handles the drum fills: turn it down and they repeat every bar, turn it up and they never do. Chaos on its own is noise, so a small model filters it. It gets rewarded for consonant intervals and practises over the chord changes before it writes anything. The CHAOS / POLICY slider decides how much say each one gets. Ten styles, and they are properly different. Funk plays a 16th-note slap line with ghost notes between the backbeats. Bebop walks the bass and puts the ride in charge of the time. Bossa runs a clave. Space strips the kit back to a pulse. Every track is built from its seed. Write the seed down and you can have that exact track again, note for note, whenever you want it. You can play over it, too. The pads are the notes of the song's key rather than a piano keyboard, so nothing you touch is wrong, and the sixteen-step lane runs in time with the song and follows your host. Both play any part you like: lead, bass, arp or pad, through that part's sound and out on its MIDI channel. Choose which sections the lane plays in - just the choruses, say - and preview it on its own without starting the song. Turn on RADIO and it keeps playing, picking a new key, mode, style and tempo for each track. You also get: • 10 styles, 6 modes, 12 keys, tempo and density • Four-operator FM engine, 6 algorithms, 11 presets, random patch • Five-part mixer, chorus, delay, plate reverb and filter • A PLAY panel: pads in the song's own key, and a 16-step lane running in time with the song and only in the sections you pick • MIDI in, so your keyboard plays whichever part you have selected • MIDI export: five tracks, one per part • Live spectrum, waveform and a view of the chaos engine at work Two Audio Units, an instrument and a MIDI processor. Each part sends on its own MIDI channel, drums on 10, so one instance can drive five instruments. The MIDI version passes your keyboard through instead of swallowing it. Both follow your host's tempo and transport. One install registers both. The app is free and nothing in it is held back. Using the Audio Units inside other apps is a one-time purchase, and each AUv3 session plays for two minutes first so you can try them properly. No account, no ads, no subscription. Works offline.
Screenshots
Verdict
The clearest difference is in-app purchases: Chord Randomizer at none against 1981 FM's 1. On price, ads, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. 1981 FM sells 1 one-off in-app purchase. Chord Randomizer asks for nothing beyond the download.
| Parameter | Chord Randomizer | 1981 FM |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (3 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 3 — better |
| Update frequency | — | Every 2 weeks |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 19 MB | 15 MB |
| Age rating | 4+ | 4+ |
| Developer | Jason Zachariah | Soft Brew Mobile |
In-app purchases
Chord Randomizer
No in-app purchases
1981 FM
- AUv3 Unlock$2.99









